Hydrogen peroxide formation in carbon clothes for enhancement of an electro-oxidation tertiary treatment for tequila vinasse wastewater

Carbon-based electrodes have been extensively used as cathodes for the electrogeneration of H2O2, which is used in the production of the hydroxyl radical center dot OH to mineralize organic compounds in several types of wastewater. Carbon cloth has been also used in combination with activated carbon for the combined adsorption and oxidation of persistent organic compounds present in tequila vinasse wastewater. Whereas most of the works regarding the H2O2 electro-generation involve relatively complex processes to enhance the catalytic activity or the electrochemically active area of these electrodes, calcination by itself represents a simple and low-cost option to enhance these cathodic and anodic functions, especially in the fabrication of large area electrodes that could be needed to treat the large amount of tequila vinasse wastewater that is produced daily. In this work, the effect of calcination at 300 degrees C and 600 degrees C of carbon clothes in the oxidation current and H2O2 production at different potentials in H2SO4 was studied. Oxidation current increased 700% upon calcination at 600 degrees C, compared to no calcination. H2O2 was produced only in a narrow range of polarizations, whereas calcination at 600 degrees C increased the generation rate from 7.1 +/- 0.3 to 17.8 +/- 0.4 mg L-1 h(-1).

Automated summary

Carbon-based electrodes are widely used for the electrogeneration of H2O2, essential for mineralizing organic compounds in wastewater. Calcination at high temperatures enhances the cathodic and anodic functions of carbon cloth electrodes, significantly increasing the oxidation current and H2O2 production. This study investigated the effect of calcination at 300 and 600 degrees Celsius on the oxidation current and H2O2 production.